Adding the values of radio button list together

I am creating a number of radio button lists on a page and each ListItem value is numeric. In the code behind I am trying to add these values together to a label i've created and based on the number returned I will display a message on the page. At present I can only get the value "1" showing as my label, in the code behind I think my addition for the radio button list items values is not correct. Any help is greatly appreciated.
ASPX PAGE:
<h1>1. Looking after yourself</h1> Personal care - things like having a shower or a bath, dreessing, going to the toilet, eating, moving about<br><br> <asp:RadioButtonList id="rbl_lookingAfterYourself" runat="server" CssClass="radioButtonList"> <asp:ListItem Value="1">I do not& ...